html {
    height: 100%;
}

body {
    margin: 0px;
    height: 100%;
}

table {
    width: 100%;
    height: 700px;
    margin-top: 0px;

}


.drog {
    width: 520px;
    height: 320px;
    background: rgba(255, 255, 255, .8);
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    border: 1px solid #fff;
    background-clip: content-box;
    padding: 10px;
    border-radius: 10px;
}


#mask {
    height: 100%;
    background: url("img/1 (82).jpg");
    /*窗口可以大小变化*/
    background-size: cover;
}